https://gcc.gnu.org/bugzilla/show_bug.cgi?id=113441
Richard Biener <rguenth at gcc dot gnu.org> changed:
What |Removed |Added
----------------------------------------------------------------------------
Keywords| |missed-optimization
Target Milestone|--- |13.3
Summary|[14 Regression] Fail to |[13/14 Regression] Fail to
|fold the last element with |fold the last element with
|multiple loop |multiple loop
--- Comment #2 from Richard Biener <rguenth at gcc dot gnu.org> ---
It might be
t.c:29:22: missed: Data access with gaps requires scalar epilogue loop
required when vectorizing the load groups. We end up with
t.c:29:22: note: === vect_analyze_data_ref_accesses ===
t.c:29:22: note: Detected single element interleaving array1[0][_8] step 4
t.c:29:22: note: Detected single element interleaving array1[1][_8] step 4
t.c:29:22: note: Detected single element interleaving array1[2][_8] step 4
t.c:29:22: note: Detected single element interleaving array1[3][_8] step 4
t.c:29:22: note: Detected single element interleaving array1[0][_1] step 4
t.c:29:22: note: Detected single element interleaving array1[1][_1] step 4
t.c:29:22: note: Detected single element interleaving array1[2][_1] step 4
t.c:29:22: note: Detected single element interleaving array1[3][_1] step 4
t.c:29:22: missed: not consecutive access array2[_4][_8] = _69;
t.c:29:22: note: using strided accesses
t.c:29:22: missed: not consecutive access array2[_4][_1] = _67;
t.c:29:22: note: using strided accesses
it's better to use signed 'm' (or uint64_t I guess), then we get
t.c:29:22: note: === vect_analyze_data_ref_accesses ===
t.c:29:22: note: Detected interleaving load array1[0][_1] and array1[0][_8]
t.c:29:22: note: Detected interleaving load array1[1][_1] and array1[1][_8]
t.c:29:22: note: Detected interleaving load array1[2][_1] and array1[2][_8]
t.c:29:22: note: Detected interleaving load array1[3][_1] and array1[3][_8]
t.c:29:22: note: Detected interleaving store array2[_4][_1] and
array2[_4][_8]
t.c:29:22: note: Detected interleaving load of size 2
t.c:29:22: note: _2 = array1[0][_1];
t.c:29:22: note: _9 = array1[0][_8];
t.c:29:22: note: Detected interleaving load of size 2
t.c:29:22: note: _18 = array1[1][_1];
t.c:29:22: note: _23 = array1[1][_8];
t.c:29:22: note: Detected interleaving load of size 2
t.c:29:22: note: _32 = array1[2][_1];
t.c:29:22: note: _37 = array1[2][_8];
t.c:29:22: note: Detected interleaving load of size 2
t.c:29:22: note: _46 = array1[3][_1];
t.c:29:22: note: _51 = array1[3][_8];
t.c:29:22: note: Detected interleaving store of size 2
t.c:29:22: note: array2[_4][_1] = _67;
t.c:29:22: note: array2[_4][_8] = _69;
and no gap peeling required.
I guess you say GCC 13 is bad as well?
